Abstract

Mate choice among early human groups and in many historical populations was subject to both demographic and social constraints, ensuring that most unions were between couples who had coinherited substantial proportions of their genomes from common ancestors. Even in populations in which close consanguineous marriage was proscribed, community endogamy would have been sufficient to ensure high levels of homozygosity. Consanguineous marriage remains the choice of an estimated 10.4% of the global population, although there has been an overall decline in its popularity, especially in developed countries. Recent studies have indicated that the shift from consanguineous marriage to panmixia has been accompanied by a reduction in homozygosity. The concomitant predicted decrease in incidence of both recessive single-gene disorders and more common adult-onset diseases will have a significant impact on the health of future generations.